DAY15&16: Python day 22 & 23

Created Pong and Crossy Road on each day, respectively.

reviewed concepts:

• creating classes
• creating class attributes using __init__()
• creating class methods using def
• inheriting attributes and methods using super().__init()__
• event listeners screen.onkey()
• distance logic using if statements with object.xcor(), object.ycor()or object.distance()
• arbitrarily refreshing screen with screen.tracer(0) and time.sleep()